Table 1.

Characteristics of different segments of the human gastrointestinal (GI) tract.

Segment	pH	Length (cm)	Mean Diameter (cm)	Mucus Average Thickness (µm)	Mucus Turnover (hour)
Stomach	0.8–5 [45]	20 [45]	NA	245 ± 200 [38]	24–48 [46]
Duodenum	~7 [38]	17–56 [47]	4 [48]	15.5 [45]	24–48 [46]
Jejunum	≥ 7 [38]	280–1000 [47]	2–2.5 [48]	15.5 [45]
Ileum	≥ 7 [38]		3 [48]	15.5 [45]
Colon	7–8 [38]	80–313 [47]	4–4.8 [48]	135 ± 25 [38]	24–48 [46]